To enable clinicians to counsel patients responsibly, evidence-based curricula about herbs and dietary supplements (H/DS) are urgently needed. The long-term objective of this project is to determine the most effective and efficient ways to deliver Internet-based curricula on H/DS and other topics to busy health professionals. Our previous research showed that an Internet-based curriculum delivered over 10 weeks was feasible, and it improved clinicians' knowledge, confidence and communication about H/DS. This project addresses questions raised in the previous study; specifically, it aims to assess the impact of two different aspects of the Internet-based curricula about H/DS: a) duration (all at once, "bolus" delivery vs. small amounts at a time over 10 weeks, "drip" delivery), and b) "push" delivery of curricular modules via email vs. "pull" delivery of access to modules on the Internet. The project will recruit at least 1,500 licensed health professionals (N=500 for Spring '04 and N=1000 for Fall '04 semester) through the North Carolina Northwest Area Health Education Center's active mailing list of over 80,000 MDs, Nurses (RNs), Pharmacists (PharmDs), Physician Assistants (Pas) and Dietitians (RDs). Continuing education (CE) credits will be available to licensed American clinicians who complete both the pre-tests and post-tests. Due to profession-specific CE regulations, RNs will only be recruited for the fall semester; because RNs are the largest professional group, this accounts for the substantially larger sample size in fall. The study design is a randomized controlled trial, comparing the impact of four approaches to electronic curriculum delivery (a."bolus" + "push"; b, + "bolus" + "pull"; c, "drip" + "push"; and d, "drip" + "pull") in a two by two factorial design. Participants in all four arms will receive the same curriculum (40 self-instructional modules, links to in-depth, evidence-based Internet sites on H/DS, and enrollment in a moderated Listserv discussion group). The three primary outcomes are pre- to post- curriculum changes in clinicians' knowledge, confidence and communication practices regarding H/DS. Predictor variables include demographic characteristics (age, gender, profession) and "technographic" characteristics, (use of and attitudes toward Internet technology). Secondary outcomes include process evaluations such as satisfaction with the curriculum and use of individual curricular components. Results from this project will guide future internet-based Continuing Education programs for busy health professionals.